Field alignment error
A form of site error caused by the direction finder antenna system not being mounted on the fore and aft line of the ship or caused by asymmetry in the structure of the vessel.
Reference: B.S. (modified)
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
Centre of buoyancy
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM